A human shoulder is a ball and socket joint made up of three bones: the humerus, scapula (i.e. shoulder blade), and clavicle (i.e. collar bone). After certain injuries, surgery or other medical treatments that affect the mobility of the shoulder, it is customary for the patient to be prescribed physical therapy. For example after shoulder operation, scar tissue may form in shoulder joint tissue (i.e. arthrofibrosis) and as such, mobility of the shoulder may suffer. A patient who has undergone shoulder surgery may not be able to return to their normal daily activities without rehabilitative therapy. Studies have shown that prolonged immobilization after shoulder surgery or injury may cause irreversible changes in articular cartilage, inhibit circulation of synovial fluid, starve joint cartilage of nutrients, and promote the development of adhesions. Gradual loss of movement in a patients shoulder is sometimes referred to as “frozen shoulder”.
Three cardinal planes are sometimes used to refer to a human body. A sagittal plane is perpendicular to the ground and divides a standing human body into left and right portions. A frontal plane is perpendicular to the ground and divides the body into posterior and anterior portions, extending laterally along a person's shoulder. A transverse plane is parallel to the ground and divides a body into upper and lower halves. Such planes may be used to define or describe an axis about which an action is performed. For example, a sagittal axis is defined as passing from posterior to anterior of a human body, formed by an intersection of sagittal and transverse planes. A frontal axis is defined as passing from left to right of a human body, formed by the intersection of frontal and transverse planes. A vertical axis passes vertically and is formed by the intersection of sagittal and frontal planes.
Commonly referenced arm motions provided by a shoulder joint are forward flexion and forward extension, abduction and adduction, internal rotation and external rotation, and horizontal abduction and horizontal adduction. For example, forward flexion and extension may describe motion performed about a frontal axis of the shoulder joint with motion in a sagittal plane. Abduction and adduction may describe motion performed about a sagittal axis of the shoulder joint with motion in a frontal plane. Horizontal abduction and horizontal adduction may describe motion performed about a vertical axis with motion in a transverse plane. Internal rotation and external rotation (or sometimes referred to as medial and lateral rotation respectively) may describe motion performed where a person's upper arm (the section of an arm from the elbow to the shoulder) rotates inward or outward about an axis extending along the upper arm through the shoulder joint (usually demonstrated with a bent elbow).
Commonly, a physician may prescribe therapeutic exercises to help a patient regain normal shoulder end range of motion. For example, a therapist may prescribe active range of motion (AROM) exercises, active assisted range of motion (AAROM) exercises, passive range of motion (PROM) exercises, and/or progressive resisted exercises (PRE) to help strengthen muscles surrounding the shoulder and break down scar tissue. AROM is defined as moving a body part without assistance of another. AAROM is defined as moving a body part with the assistance of another. PROM is defined as moving a body part with only the assistance of another. PRE are defined as movement of a body part against or opposing applied outside resistance.
As an example, to increase range of motion in the shoulder, a physical therapist may apply passive range of motion therapy. For example, to increase range of motion, the therapist may manually place appropriate rotational force on a patient's shoulder joint by rotating the patient's arm. After a desired force is achieved, the therapist may return the patient's arm to an original position to complete a cycle. Such therapy is applied on a frequent basis and maximum and minimum position angles are measured to quantify progress.
However, such manual methods are inconvenient because either the therapist or the patient has to travel on a frequent basis, possibly for many months. As such, shoulder therapy via a physical therapist is time-consuming, inefficient and costly.
Efforts may be made to train others, for example, the wife or husband of the patient, to perform these exercises. However, such training efforts have poor results, however, due to lack of patient and caregiver compliance and insufficient training to replicate the skill of a licensed therapist.
Such issues with manual methods have led to the development of machines that attempt to reproduce the capabilities of a licensed physical therapist, allowing therapy to be provided without requiring the patient or a therapist to travel and spend time providing therapy. For example, a therapy machine may be provided to a patient so that the patient may engage in therapy by themselves. However, current shoulder range of motion therapy machines have various problems. Common range of motion therapy machines individually are not able to provide end range of motion therapy for all of the above described motions, and as such, multiple different machines are required to be purchased to provide complete therapy. Further, common range of motion therapy machines are not appropriately configured for active therapy modalities. Furthermore, common range of motion therapy machines are not configured to record usage data, which may help track progress or check on patient compliance.
Therefore, there exists a need for a shoulder range of motion therapy machine or device that can rotate a shoulder of a patient to provide both active and passive range of motion therapies for all the above mentioned motions, and record usage data to track progress and check patient compliance